scholarly journals Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine With Partial-Admission

2020 ◽  
Author(s):  
Patrick H. Wagner ◽  
Jan Van herle ◽  
Jürg Schiffmann
Keyword(s):  
Steam Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Tip Clearance ◽  
Experimental Results ◽  
Partial Admission ◽  
Blade Tip

Abstract A micro steam turbine with a tip diameter of 15 mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kg h−1 and 2, respectively, the turbine yields a power of 34 W and a total-to-static isentropic efficiency of 37%. The steam turbine is conceived as a radial-inflow, low-reaction (15%), and partial admission (21%) machine. Since the steam mass flow rate is limited by the heat provided of the system (solid oxide fuel cell), a low-reaction and high-power-density design is preferred. The partial-admission design allows for reduced losses: The turbine rotor and stator blades are prismatic, have a radial chord length of 1 mm and a height of 0.59 mm. Since the relative rotor blade tip clearance (0.24) is high, the blade tip leakage losses are significant. Considering a fixed steam supply, this design allows to increase the blade height, and thus reducing the losses. The steam turbine drives a fan, which operates at low Mach numbers. The rotor is supported on dynamic steam-lubricated bearings; the nominal rotational speed is 175 krpm. A numerical simulation of the steam turbine is in good agreement with the experimental results. Furthermore, a novel test rig setup, featuring extremely-thin thermocouples (ϕ0.15 mm) is investigated for an operation with ambient and hot air at 220 °C. Conventional zero and one-dimensional pre-design models correlate well to the experimental results, despite the small size of the turbine blades.

scholarly journals Theoretical and Experimental Investigation of a 34 Watt Radial-Inflow Steam Turbine with Partial-Admission

2020 ◽  
Author(s):  
Patrick Wagner ◽  
Jan Van herle ◽  
Jurg Schiffmann
Keyword(s):  
Steam Turbine ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Tip Clearance ◽  
Experimental Results ◽  
Tip Leakage ◽  
Hot Air ◽  
Partial Admission ◽  
Blade Tip

Abstract A micro steam turbine with a tip diameter of 15 mm was designed and experimentally characterized. At the nominal mass flow rate and total-to-total pressure ratio of 2.3 kg/h and 2, respectively, the turbine yields a power of 34 W and a total-to-static isentropic efficiency of 37 %. The steam turbine is conceived as a radial-inflow, low-reaction (15 %), and partial admission (21 %) machine. Since the steam is limited in the system (solid oxide fuel cell), a low-reaction and high-power-density design is preferred. The partial-admission design allows for reduced losses: The turbine rotor and stator blades are prismatic, have a radial chord length of 1 mm and a height of 0.59 mm. Since the relative rotor blade tip clearance (0.24) is high, the blade tip leakage losses are significant. Considering a fixed steam supply, this design allows to increase the blade height, and thus reducing the losses. The steam turbine drives a fan, which operates at low Mach numbers. The rotor is supported on dynamic steam-lubricated bearings; the nominal rotational speed is 175 krpm. A numerical simulation of the steam turbine is in good agreement with the experimental results. Furthermore, a novel test rig setup, featuring extremely-thin thermocouples (0.15 mm) is investigated for an operation with ambient and hot air at 220 °C. Conventional zero and one-dimensional pre-design models correlate well to the experimental results, despite the small size of the turbine blades.

Numerical Simulation of Steady Air Injection Flow Control Effects on a Transonic Axial Flow Compressor

2012 ◽  
Vol 224 ◽  
pp. 352-357
Author(s):  
Islem Benhegouga ◽  
Ce Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Leading Edge ◽  
Air Injection ◽  
Axial Flow Compressor ◽  
Blade Tip ◽  
Flow Compressor

In this work, steady air injection upstream of the blade leading edge was used in a transonic axial flow compressor, NASA rotor 37. The injectors were placed at 27 % upstream of the axial chord length at blade tip, the injection mass flow rate is 3% of the chock mass flow rate, and 3 yaw angles were used, respectively -20°, -30°, and -40°. Negative yaw angles were measured relative to the compressor face in opposite direction of rotational speeds. To reveal the mechanism, steady numerical simulations were performed using FINE/TURBO software package. The results show that the stall mass flow can be decreased about 2.5 %, and an increase in the total pressure ratio up to 0.5%.

3D Direct and Inverse Design Using NS Equations and the Adjoint Method for Turbine Blades

2010 ◽  
Author(s):  
D. X. Wang ◽  
Y. S. Li
Keyword(s):  
Case Studies ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Adjoint Method ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Inverse Design ◽  
Entropy Generation Rate ◽  
Blade Geometry

Presented in this paper are two case studies on the application of the adjoint method to turbine blading aerodynamic design optimization. One case involves the use of the adjoint method in a direct design, where the blade geometry is changed to reduce the entropy generation rate of a power turbine subject to mass flow rate and pressure ratio constraints. The other case investigates the use of the adjoint method in an inverse design, where the blade geometry is changed to approach a target static pressure loading on a blade surface, also subject to mass flow rate and pressure ratio constraints. Promising results are obtained for the two cases. Also examined in the two case studies is the application of the adjoint method to flow field with big separations, which can be detrimental to the convergence of an adjoint solution due to its linearity.

Application of Casing Circumferential Grooves to Counteract the Influence of Tip Clearance

2008 ◽  
Author(s):  
Victor Mileshin ◽  
Igor Brailko ◽  
Andrew Startsev
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Blade Height ◽  
Transonic Compressor

Widening of surge margin of a transonic compressor stage is the main objective of the paper. This stage is a typical middle stage of a modern high pressure compressor (HPC) with decreased number of stages. Hot tip clearance of the stage being integrated into a six-stage HPC providing total pressure ratio π* HPC ≥ 12 and mass flow-rate < 16 kg/sec is estimated at 2.5 – 3% of blade height and is classified as a large tip clearance. In this paper experimental and 3D viscous numerical performances of the stage are obtained for two values of rotor tip clearance — equal to 0.76% (small size) and 2.66% (large size) of blade height. In doing so, tip clearance enlargement from 0.76% to 2.66% has been made by increase of casing (shroud) radius. This increase is manufactured as a circumferential trench (recess) with axial width 30% larger than rotor axial chord. Below this tip clearance is called “recessed” tip clearance. A distinguishing feature of leakage flow in case of large tip clearance is a formation of reversed flow near rotor casing. This backflow being intensified by throttling causes increase of incidence at the rotor leading edge and development of rotor stall. Casing treatments are intended to inhibit and delay the process. Among them circumferential grooves is the simplest casing treatment. Investigated in this paper casing circumferential grooves cover 82% of rotor axial chord. Numerical visualization of the near-casing streamlines demonstrates that tip leakage flow drains into the casing grooves giving rise to extended domains of positive axial velocity. Calculated mass flow-rate through groove’s cross-section demonstrates maximum over the rotor blade tip (flow into the groove) and minimum at mid-pitch (flow out of the groove). Amplitude of this variation depends on the groove location and stage throttling.

Impact of Passive Tip-Injection on the Performance of Partially Shrouded Turbines: Basic Concept and Preliminary Results

2013 ◽  
Author(s):  
Pouya Ghaffari ◽  
Reinhard Willinger
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Blade Tip ◽  
Tip Injection ◽  
The Impact

In terms of efficiency improvement many methods for reducing the blade tip-leakage mass flow rate have been proposed. Some of these methods are based on increasing the flow resistance with aid of geometrical modifications of the blade tip (squealers, winglets, shrouded blades, etc.) whereas other methods take advantage of aerodynamical resistance with passive tip-injection as an example. The objective of this paper is a combination of both methods in order to achieve higher reduction in tip-leakage mass flow rate. In the first part of this work necessary characteristic parameters of modern low pressure turbine blades in aircraft gas turbines are estimated. These parameters are taken into consideration to calculate the range of physical quantities influencing tip-leakage flow. Subsequently a two dimensional flow model is obtained with the so called discharge coefficient as the ratio of the actual tip gap mass flow rate to its highest possible value. The investigations are based on dimensionless calculations. In the end the results obtained from dimensionless 2D CFD-simulations are presented and compared with the analytical results. This leads to conclusions regarding the impact of various parameters on the effectiveness of the passive tip-injection.

Behavior of Thermal Effects and Velocity-Slip on Performance of Externally Pressurized Porous Incompressible Gas Thrust Bearing

1979 ◽  
Vol 46 (2) ◽  
pp. 465-468 ◽  
Author(s):  
V. K. Kapur ◽  
J. S. Yadav
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Effects ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Velocity Slip ◽  
Experimental Results ◽  
Slip Condition ◽  
Static Stiffness

In the present analysis, the interactions of thermal effects and velocity slip on the performance of externally pressurized porous incompressible gas thrust bearing have been studied. Numerical results for load capacity, mass flow rate, and static stiffness have been obtained and their behavior is illustrated in figures. The results for slip as well as no-slip condition have also been compared with the experimental results of Gargiulo and Gilmour [7].

scholarly journals Comparison of Power Distribution, Losses and Efficiencies of a Steam Turbine with and without Extractions

2020 ◽  
Vol 14 (4) ◽  
pp. 480-487
Author(s):  
Vedran Mrzljak ◽  
Sandi Baressi Šegota ◽  
Hrvoje Meštrić ◽  
Zlatan Car
Keyword(s):  
Steam Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Distribution ◽  
Power Losses ◽  
Base Process ◽  
Energy And Exergy ◽  
Simultaneous Decrease ◽  
Dominant Influence

The paper presents an analysis of two steam turbine operation regimes - regime with all steam extractions opened (base process) and regime with all steam extractions closed. Closing of all steam extractions significantly increases turbine real developed power for 5215.88 kW and increases turbine energy and exergy losses with simultaneous decrease of turbine energy and exergy efficiencies for more than 2%. First extracted steam mass flow rate has a dominant influence on turbine power losses (in comparison to turbine maximum power when all of steam extractions are closed). Cumulative power losses caused by steam mass flow rate extractions are the highest in the fourth turbine segment and equal to 1687.82 kW.

Design and Testing of a Can Combustor for a Small Gas Turbine Application

2013 ◽  
Author(s):  
K. V. L. Narayana Rao ◽  
N. Ravi Kumar ◽  
G. Ramesha ◽  
M. Devathathan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Pressure Loss ◽  
High Energy ◽  
Experimental Results ◽  
High Mass ◽  
Test Facility ◽  
Design Requirements

Can type combustors are robust, with ease of design, manufacturing and testing. They are extensively used in industrial gas turbines and aero engines. This paper is mainly based on the work carried out in designing and testing a can type combustion chamber which is operated using JET-A1 fuel. Based on the design requirements, the combustor is designed, fabricated and tested. The experimental results are analysed and compared with the design requirements. The basic dimensions of the combustor, like casing diameter, liner diameter, liner length and liner hole distribution are estimated through a proprietary developed code. An axial flow air swirler with 8 vanes and vane angle of 45 degree is designed to create a re-circulation zone for stabilizing the flame. The Monarch 4.0 GPH fuel nozzle with a cone angle of 80 degree is used. The igniter used is a high energy igniter with ignition energy of 2J and 60 sparks per minute. The combustor is modelled, meshed and analysed using the commercially available ansys-cfx code. The geometry of the combustor is modified iteratively based on the CFD results to meet the design requirements such as pressure loss and pattern factor. The combustor is fabricated using Ni-75 sheet of 1 mm thickness. A small combustor test facility is established. The combustor rig is tested for 50 Hours. The experimental results showed a blow-out phenomenon while the mass flow rate through the combustor is increased beyond a limit. Further through CFD analysis one of the cause for early blow out is identified to be a high mass flow rate through the swirler. The swirler area is partially blocked and many configurations are analysed. The optimum configuration is selected based on the flame position in the primary zone. The change in swirler area is implemented in the test model and further testing is carried out. The experimental results showed that the blow-out limit of the combustor is increased to a good extent. Hence the effect of swirler flow rate on recirculation zone length and flame blow out is also studied and presented. The experimental results showed that the pressure loss and pattern factor are in agreement with the design requirements.

Flow Field in the Tip Gap of a Planar Cascade of Turbine Blades

1989 ◽  
Vol 111 (3) ◽  
pp. 276-283 ◽  
Author(s):  
M. Yaras ◽  
Yingkang Zhu ◽  
S. A. Sjolander
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Difference ◽  
Good Accuracy ◽  
Flow Direction ◽  
Turbine Blades ◽  
Rate Distribution ◽  
Velocity Magnitude ◽  
The Relationship

Measurements are presented for the flow in the tip gap of a planar cascade of turbine blades. Three clearances of from 2.0 to 3.2 percent of the blade chord were considered. Detailed surveys of the velocity magnitude, flow direction, and total pressure within the gap were supplemented by blade surface and endwall static pressure measurements. The results help to clarify the relationship between the leakage mass flow rate distribution and the driving pressure differences. It was found that even for the present relatively large clearances, fluid near the endwall experiences a pressure difference that is comparable with the blade pressure difference. It is also shown that a simple model can predict with good accuracy the mass flow rate distribution and the magnitude and direction of the velocity vectors within the gap.

Design and Internal Flow Analysis of a Ducted Contra-Rotating Axial Flow Fan

2014 ◽  
Author(s):  
Ali Mohammadi ◽  
Masoud Boroomand
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Optimum Operating ◽  
Axial Flow Fan ◽  
Design Algorithm ◽  
Flow Solver ◽  
Operating Points

This paper presents the design procedure of a ducted contra-rotating axial flow fan and investigates the flow behavior inside it using ANSYS CFX-15 flow solver. This study investigates parameters such as pressure ratio, inlet mass flow rate and efficiency in different operating points. This system consists of two rotors with an outer diameter of 434 mm and an inner diameter of 260 mm which rotate contrary to each other with independent nominal rotational speeds of 1300 rpm. Blades’ maximum thickness and rotational speeds of each rotor will be altered as well as the axial distance between the two rotors to investigate their effect on the overall performance of the system. Designed to deliver a total pressure ratio of 1.005 and a mass flow rate of 1.8 kg/s at nominal rotational speeds, this system proves to be much more efficient compared to the conventional rotor-stator fans. NACA-65 airfoils are used in this analysis with the necessary adjustments at each section. Inverse design method is used for the first rotor and geometrical constraints are employed for the second one to have an axial inlet and outlet flow without using any inlet or outlet guide vanes. Using free vortex swirl distribution method, characteristic parameters and the necessary data for 3D generation of this model are obtained. The appropriate grid is generated using ATM method in ANSYS TurboGrid and the model is simulated in CFX-15 flow solver by employing k-ε turbulence model in the steady state condition. Both design algorithm and simulation analysis confirm the high anticipated efficiency for this system. The accuracy of the design algorithm will be explored and the most optimum operating points in different rotational speed ratios and axial distances will be identified. By altering the outlet static pressure of the system, the characteristic map is obtained.

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